The Mental Health Conservatorship is part of the Lanterman-Petris-Short (LPS) Act 1967. An LPS Conservatorship is the legal term used in California that gives one adult (the conservator) the responsibility for overseeing the comprehensive medical (mental) treatment for an adult (conservatee) who has a serious mental illness. Guidelines for the involuntary mental health treatment are under the California Welfare and Institutions Codes 5200.
The full guide can be found here: https://namila.org/resources/guide-to-lps-conservatorship
A big thank you to NAMI West Los Angeles for creating this guide!